The invention relates to a sleeve joint between two pipe sections of a high-pressure line, which pipe sections each comprise a fluid-tight inner jacket made of a thermoplastic material and a reinforced outer jacket, the inner jackets being attached to one another by means of a fluid-tight weld and the outer jackets each being joined to one another by means of a connecting sleeve.
A sleeve joint of this type is disclosed in WO-A 9512086. With this known sleeve joint a bush-shaped sleeve is used, into which the ends of the pipe sections to be joined are inserted. Two conical rings are pressed onto the sleeve, which rings have to produce the clamping connection. With this arrangement the ends concerned are locally deformed as a consequence of rings provided on the interior surface of the sleeve.
This known sleeve joint has various disadvantages. First of all the bush-shaped sleeve and the pipe sections have to be constructed to fit closely into one another such that the desired strength and tightness of the seal can actually be achieved in practice. Furthermore, the rings must be pressed onto the sleeve using fairly high forces, for which special tools are needed.
The aim of the invention is to provide a sleeve joint which does not have these disadvantages. Said aim is achieved in that the connecting sleeve comprises shells which have serrations on the inside, as well as clamping means for clamping the shells on the pipe sections in such a way that the internal serrations are made to interact with the outer jackets of the pipe sections.
The shells can be slid fairly easily laterally onto the ends of the pipe sections to be connected, after which the clamping means can be tightened.
To ensure the desired retaining action, the serrations can be barb-shaped and located in two regions, the barbs in the one region being oriented in the opposite direction to those in the other region.
The serrations are forced into the external surface of the pipe sections on tightening the clamping means, as a result of which said external surface is locally compressed somewhat. The surface of the pipe sections does not have to be specially prepared, whilst a firm joint can nevertheless be obtained.
According to a first possibility, two shells are provided, each of which extends over both pipe sections.
Both shells can have wedge-shaped external clamping surfaces which interact with clamping pieces which are provided on the inside with corresponding wedge-shaped clamping surfaces and can be slid in the axial direction onto the clamping surfaces of the shells.
According to a second possibility, each pipe section can be fitted with a pair of shells, which pairs are joined to one another by means of a yoke.
In this case, each pair of shells is clamped on the relevant pipe section by means of a clamping bracket surrounding said pair, a tensile element being fixed to said clamping brackets of the two pairs.
Each clamping bracket has a recess which extends all round and in which the pair of shells is accommodated.
By way of example, each clamping bracket can comprise two identical clamping bracket halves, in each of which one shell is accommodated.
Reference is made to the sleeve joint as disclosed in EP-A 152 752. With said known sleeve joint a sleeve comprising two shell halves is used. Both the shell halves and the pipe sections are provided on those surfaces thereof that face one another with a sinusoidal ring pattern which is intended to ensure good force transfer.